When coupling the Free Piston Engine (FPE) to the Permanent Magnet Linear Synchronous Machine (PMLSM) to produce electrical energy, its intrinsic multi-directional and non-linear dynamics have been typically described in a simplified mono-directional and linear fashion when considering a system-level modelling approach. This paper presents a detailed, multi-directional, multi-domain model of the FPE and PMLSM. The model was implemented in an opposed-piston free-piston engine configuration and validated against experimental data captured from a prototype with identical parameters. The simulation results indicate a strong correlation to the experimental data, which captured the dominant dynamics of the FPE and proved the satisfactory accuracy and performance of the model. This study considers the characteristic multi-directional nature and non-linearity of the machine dynamics and its interactions with multi-physical domains such as electrical, mechanical, and pneumatic.
Keywords Free Piston Engine (FPE), Permanent Magnet Linear Synchronous Machine (PMLSM), Non-Linear Modelling, Multi-Domain Modelling, In-Cylinder Modelling